Perylene (Per) was reacted with AsF5 dissolved in liquid SO2 to produce Per(AsF6)2. Far infrared absorption showed absorption by AsF6−. Nuclear magnetic resonance of 19F consisted of a quartet formed by indirect nuclear–nuclear coupling. The change of mass through the reaction indicated the formula Per(AsF6)2. Mass spectroscopy showed bonding between perylene and F and indicated no SO2 solvent in the sample. This solvent-free material does not conduct electrically. X-ray diffraction showed that the structure has an orthorhombic cell. Exposure to air changes the sample weight and colour, and results in conduction with semiconducting properties and reduced bonding between AsF6− and perylene.